These studies are directed toward the analysis and synthesis of molecular assemblies with common and rare amino acids including: 1) preparation of analogs of Corticotropin Releasing Factor with "unnatural amino acids" in a search for antagonists or prolongation of activity; 2) preparation of fragments of Corticotropin Releasing Factor for determination of structures necessary for binding to its receptors; 3) development of new techniques in peptide synthesis including use of selenophenol as a deprotecting agent; 4) large scale preparation of hormones such as Corticotropin Releasing Factor and renin inhibitor for clinical use; 5) combinations of Alpha, Beta-unsaturated amino acids with nucleotides such as 5-aminoimidazole-4-(N-fumarylocarboxamide) ribotide and adenylofumarate, to study their action on neoplastic tissue and viral replication; 6) partial sequences of cholecystokinin and correlation of structure with function; 7) preparation of partial sequences of viral peptides and conjugation with carriers for the purpose of producing antibodies.